Bài 1:\(a,-12+89-88+211=\left(-12-88\right)+\left(89+211\right)=-100+300=200\\ b,-1983+67+1980+3+33=\left(-1983+1980+3\right)+\left(67+33\right)=0+100=100\)
Bài 2:
\(a,125-\left\{38-\left[-\left(+5\right)+\left(-23+54\right)\right]\right\}=125-\left[38-\left(-5+31\right)\right]=125-\left(38-26\right)=125-12=113\)
\(b,73-\left\{-\left[-82+\left(-33-91\right)\right]+\left(-45\right)\right\}=73-\left\{-\left[-82+\left(-124\right)\right]-45\right\}=73-\left[-\left(-206\right)-45\right]=73-\left(206-45\right)=73-161=-88\)
Bài 5:
A=-2+(-2)+(-2)+...+(-2)
=-2x501=-1002